The invention concerns a drive device for a moveable furniture part comprising a latching element displaceable in a cardioid curve-like sliding track. The sliding track has a closing portion in which the latching element moves upon closing of the moveable furniture part, a locking portion having a latching recess in which the latching element is held in the locking position, an opening portion in which the latching element is displaceable upon opening of the moveable furniture part, and a first connecting portion, by way of which the latching element is moveable from the opening portion into the closing portion when the furniture part is opened. The invention also concerns an article of furniture comprising a furniture carcass, a moveable furniture part and such a drive device for the moveable furniture part.
Drive devices for moveable furniture parts in the form of lockable ejection devices have already been known for many years in the furniture fitting industry. In that case, unlocking of the ejection device is triggered by movement (pushing or pulling) of the moveable furniture part out of the closed position, whereby the moveable furniture part is automatically ejected or opened.
In that respect, locking by way of a sliding track in the form of a cardioid curve has become established as the common kind of locking action. The latching element connected to an ejection element is held in the locking portion of that sliding track, whereby the moveable furniture part is in the closed position. By pressing against the moveable furniture part, the latching element is also moved out of the locking portion and passes into an opening portion. As soon as that is reached, an ejection force storage means can be relieved of stress and ejects the moveable furniture part in the opening direction. In that respect, that opening portion is approximately as long as the ejection travel of the ejection force storage means. As soon as the ejection force storage means has been completely unloaded, therefore, the latching element is also disposed at the end of the opening portion of the sliding track. From that position, the moveable furniture part can be further opened manually in a freely running movement.
In a closing movement or active retraction movement by way of a retraction device, the latching element is not moved back through the opening portion again, but is deflected into a closing portion by the configuration of the sliding track. For that purpose, a transitional region is provided between the opening portion and the closing portion. That transitional region can also be referred to as a connecting portion. In commonly used drive devices, the opening portion has a length of between about 3 cm and 20 cm between the latching recess and the first connecting portion. That travel distance, however, can be individually adjusted and is dependent on the size of the moveable furniture part and other parameters.
In order to restore secure locking of the latching element in the latching recess, the latching element or the control projection has to be moved through the closing portion in known drive devices with a cardioid curve-like sliding track (see for example Austrian patent application A 614/2011) which is of earlier priority and which forms a prior right. If however the ejection movement is interrupted because of incorrect operation, for example by the moveable furniture part still being stopped during the ejection movement, the latching element remains in the opening portion. If now the operator wants to close the furniture part again, it is no longer possible for locking of the latching element to take place in the latching recess as the latching element cannot move from the opening portion into the locking portion by virtue of the configuration of the sliding track. Secure locking would only be possible if the operator moves the moveable furniture part in the opening direction until the latching element has reached the first connecting portion and the latching element passes into the closing portion upon the furniture part being closed again.